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| United States Patent |
5,627,056
|
|
Casey
, et al.
|
May 6, 1997
|
Method of synthesizing lipids and cosmetic composition comprising them
Abstract
An efficient method of producing phytosphingosine-containing ceramide one
comprising: (a) obtaining a phytosphingosine base from
tetraacetylphytosphingosine (TAPS) by a deacetylation reaction wherein the
TAPS is produced by fermentation of cells of the F-60-10 mating type
strain of Hansenula ciferrii using a fed-batch mode and a non-fermentable
carbon source; and (b) coupling together the phytosphingosine base and a
fatty acid/.omega.-hydroxy fatty acid component wherein the
.omega.-hydroxy fatty acid component is prepared by a process which
includes Kolbe synthesis.
| Inventors:
|
Casey; John (Wellingborough, GB);
Cheetham; Peter S. (Harrold, GB);
Harries; Peter C. (Risely, GB);
Hyliands; Della (St. James, GB);
Mitchell; John T. (Bedford, GB);
Rawlings; Anthony V. (Wyckoff, NJ)
|
| Assignee:
|
Elizabeth Arden Co., Division of Conopco, Inc. (New York, NY)
|
| Appl. No.:
|
386140 |
| Filed:
|
February 9, 1995 |
Foreign Application Priority Data
| Nov 03, 1992[GB] | 9223001 |
| Apr 03, 1993[GB] | 9306973 |
| Aug 10, 1993[GB] | 9316629 |
| Current U.S. Class: |
435/134; 424/401; 435/128; 435/129; 435/930; 554/35; 554/40; 554/41; 554/42; 554/69 |
| Intern'l Class: |
C12P 007/64; C12N 001/00; C12N 001/14 |
| Field of Search: |
424/401
435/134,128,129,930
554/35,40-42,69
|
References Cited
U.S. Patent Documents
| 4275162 | Jun., 1981 | Beppu | 435/196.
|
| 4782019 | Nov., 1988 | Kokusho | 435/89.
|
| 4950688 | Aug., 1990 | Bowser et al. | 514/847.
|
| 5198210 | Mar., 1993 | Critchley et al. | 424/78.
|
| 5202357 | Apr., 1993 | Bowser et al. | 514/847.
|
| 5326565 | Jul., 1994 | Critchley et al. | 424/401.
|
| Foreign Patent Documents |
| 0097059 | Dec., 1983 | EP.
| |
| 0482860 | Apr., 1992 | EP.
| |
| 2178312 | Feb., 1987 | GB.
| |
| 2213723 | Aug., 1989 | GB.
| |
| WO94/26919 | Nov., 1994 | WO.
| |
| WO95/11881 | May., 1995 | WO.
| |
Other References
International Search Report in International Patent Application No. PCT/GB
93/02230.
Pascher, I., "Synthesis of Galactosylphytosphingosine and
Galactosyl-ceramides Containing Phytosphingosine", Chemistry and Physics
of Lipids, vol. 12, (1974), pp. 303-315.
Stodola, F. et al., "Formation of Extracellular Sphingolipids by
Microorganisms", The Journal of Biological Chemistry, vol. 235, No. 9,
Sep. 1960, pp. 2584-2585.
Wickerham, L. et al., "Formation of Extracellular Sphingolipides by
Microorganisms", Journal of Bacteriology, vol. 80, (1960), pp. 484-491.
Green, M. et al., "Studies on the Production of Sphingolipid Bases by the
Yeast, Hansenula Ciferri", Biochimica et Biophysica ACTA, Lipids and Lipid
Metabolism, vol. 98, (1965), pp. 582-588.
Data Brochure--"Yeast Derived Ceramides". Gist-Brocades, Apr. 1992.
|
Primary Examiner: Kishore; Gollamudi S.
Attorney, Agent or Firm: Mitelman; Rimma
Parent Case Text
This is a divisional of U.S. application Ser. No. 08/146,550, filed Nov. 2,
1993, now abandoned.
Claims
We claim:
1. A method of producing a phytosphingosine-containing ceramide one having
the general structure (1):
##STR10##
where R represents a linear or branched, saturated or unsaturated,
hydroxylated or non-hydroxylated aliphatic hydrocarbon having from 8 to 28
carbon atoms;
R.sub.1 represents H, a phosphate residue, a sulphate residue or a sugar
residue
Z is --OH or an epoxy oxygen
a is an integer of from 7 to 50
b is an integer of from 10 to 100
m is 0 or 1
x is an integer of from 12 to 20;
y is an integer of from 20 to 40
z is 0 or an integer of from 1 to 4
comprising:
(a) obtaining a phytoshingosine base from tetraacetylphytosphingosine by a
deacetylation reaction wherein the tetraacetylphytosphingosine is produced
by fermentation of cells of the F-60-10 mating type strain of Hansenula
ciferrii using a fed-batch mode and a non-fermentable carbon source; and
(b) coupling together the phytosphingosine base and a fatty
acid/.omega.-hydroxy fatty acid component having the general structure (2)
via an amide linkage:
##STR11##
where Z is --OH or an epoxy oxygen
a is an integer of from 7 to 50
b is an integer of from 10 to 100
m is 0 or 1
x is an integer of from 12 to 20
y is an integer of from 20 to 40
z is 0 or an integer of from 1 to 4
wherein the fatty acid/.omega.-hydroxy fatty acid component having the
general structure (2) is prepared by linking together an .omega.-hydroxy
fatty acid having the structure (3):
OH--(C.sub.a H.sub.b)--(CHOH).sub.m --COOH (3)
and a fatty acid having the general structure (4)
##STR12##
2. A method according to claim 1 wherein the fermentation of cells of the
F-60-10 mating type strain of Hansenula ciferrii (step (a)) is carried out
in the presence of a solvent chosen from ethanol, methanol and mixtures
thereof.
3. A method according to claim 1 wherein the fermentation of cells of the
F-60-10 mating type strain of Hansenula ciferrii is carried out in the
presence of a surfactant selected from the group consisting of Tween and
Triton.
4. A method according to claim 1 wherein the of cells of the F-60-10 mating
type strain of Hansenula ciferrii is carried using the non-fermentable
carbon source glycerol.
5. A method according to claim 1 wherein the fermentation of cells of the
F-60-10 mating type strain of Hansenula ciferrii is carried out in the
presence of a tetraacetylphytosphingosine precursor selected from the
group consisting of palmitic acid, serine and mixtures thereof.
6. A method according to claim 1 wherein the fermentation of cells of the
F-60-10 mating type strain of Hansenula ciferrii is carried out at
30.degree. C.
7. A method according to claim 1 wherein the phytosphingosine base and
component (2) are linked by chemical or enzymatic routes.
Description
FIELD OF THE INVENTION
This invention relates to a method of synthesising
phytosphingosine-containing ceramide one structures plus cosmetic
compositions comprising these structures.
BACKGROUND TO THE INVENTION
Ceramides are an important group of lipids, members of which are found in
the epidermis of mammals. Skin ceramides are believed to play an important
role in the water permeability properties of the skin, providing an
epidermal water-barrier which functions to give increased strength to the
skin structure and to decrease water loss and so improve the condition of
the skin.
Ceramides are N-acylated sphingosine bases. Sphingosine bases are of
variable chain length and have the general formula (i):
CH.sub.3 (CH.sub.2).sub.x ACHOHCH(NH.sub.2)CH.sub.2 OH (i)
where A is --CH.dbd.CH-- (sphingosine), --CH.sub.2 CHOH--(phytosphingosine)
or --CH.sub.2 CH.sub.2 -- (dihydrosphingosine), and where x is generally
in the broad range 7 to 27, more typically in the range 10 to 16. It
should be noted that sphingosines contain asymmetric carbon atoms and so
various stereoisomers are possible. Sphingosine/ceramides from especially
mammalian sources are all the D-erythro isomer and
phytosphingosine/phytoceramides the D-D-erythro isomer. Seven
distinguishable groups of ceramides have been identified in pig and human
epidermis. Each group consists of molecules of varying fatty acid chain
length. The structures of typical skin ceramides are described in the
paper entitled "Ceramides of Pig Epidermis: Structure Determination" by P.
W. Wertz and D. T. Downing in Journal of Lipid Research, Vol 24, 1983,
pages 759-765.
Because of their properties it is known to use ceramides, ceramide
derivatives and also pseudoceramides (synthetic molecules which have
properties similar to those of naturally occurring ceramides) as
components of skin care compositions.
It is difficult to extract ceramides from natural sources, and in some
cases the resulting product is not acceptable for cosmetic compositions.
Furthermore, ceramides are difficult and expensive to synthesise
chemically.
It has been proposed in EP 0 097 059 to synthesise N-[omega-(O-linoleoyl)
23-cis-dotriacontenoyl] sphingosine by chemically synthesising an
appropriate sphingosine component and linking this to an appropriate acid.
The paper "Formation of Extracellular Sphingolipids by Microorganisms" by
H. G. Maister et. al. in Appl Microbiol vol 10, page 401 to 406 describes
a process for producing tetraacetyl phytosphingosine (TAPS) from the
F-60-10 mating type strain of the yeast Hansenula ciferrii. This process
uses glucose as a carbon source in a batch mode fermentation at 25.degree.
C. The process, however, is not very efficient, and while it can yield
sufficient TAPS for experimental purposes the yield is too low to be
practicable for commercial purposes. The TAPS produced is the D-D-erythro
isomer, the same as occurs in human skin.
The present inventors have derived a modified process for producing TAPS
from Hansenula ciferrii that is much more efficient and which is then used
as a component of commercial production of phytosphingosine-containing
ceramide one.
DISCLOSURE OF THE INVENTION
Accordingly the present invention provides a method of producing a
phytoshingosine-containing ceramide one having the general structure (1):
##STR1##
where
R represents a linear or branched, saturated or unsaturated, hydroxylated
or non-hydroxylated aliphatic hydrocarbon having from 8 to 28 carbon
atoms;
R.sub.1 represents H, a phosphate residue, a sulphate residue or a sugar
residue
Z is --OH or an epoxy oxygen
a is an integer of from 7 to 50
b is an integer of from 10 to 100
m is 0 or 1
x is an integer of from 12 to 20
y is an integer of from 20 to 40
z is 0 or an integer of from 1 to 4 comprising:
(a) obtaining a phytoshingosine base from TAPS by a deacetylation reaction
wherein the TAPS is produced by fermentation of cells of the F-60-10
mating type strain of Hansenula ciferrii using a fed-batch mode and a
non-fermentable carbon source; and
(b) coupling together the phytosphingosine base and a fatty acid/hydroxy
fatty acid component having the general structure (2) via an amide
linkage:
##STR2##
where
Z is --OH or an epoxy oxygen
a is an integer of from 7 to 50
b is an integer of from 10 to 100
m is 0 or 1
x is an integer of from 12 to 20
y is an integer of from 20 to 40
z is 0 or an integer of from 1 to 4
wherein the fatty acid/hydroxy fatty acid component having the general
structure (2) is prepared by linking together an .omega.-hydroxy fatty
acid having the structure (3)
OH--(C.sub.a H.sub.b)--(CHOH).sub.m --COOH (3)
and a fatty acid having the general structure (4)
##STR3##
the .omega.-hydroxy fatty acid (3) being prepared by a process which
includes Kolbe synthesis.
The present invention also provides a method of producing a fatty
acid/.omega.-hydroxy acid component having the general structure (2):
##STR4##
where
Z is --OH or an epoxy oxygen
a is an integer of from 7 to 50
b is an integer of from 10 to 100
m is 0 or 1
x is an integer of from 12 to 20
y is an integer of from 20 to 40
z is 0 or an integer of from 1 to 4
wherein an .omega.-hydroxy fatty acid having the structure (3):
OH--(C.sub.a H.sub.b)--(CHOH).sub.m --COOH (3)
is linked to a fatty acid having the general structure (4):
##STR5##
the .omega.-hydroxy fatty acid (3) being prepared by a process which
includes Kolbe synthesis.
Preferably the fermentation of Hansenula ciferrii to produce TAPS is
conducted at 30.degree. C.
Surprisingly, the inventors have discovered that yields are further
increased when the fermentation of Hansenula ciferrii is carried out in
the presence of a solvent selected from ethanol, methanol and mixtures
thereof. The fermentation is therefore preferably conducted in the
presence of such solvents.
Additionally yields are noted to be improved when the fermentation of
Hansenula ciferrii is carried out in the presence of a surfactant.
Examples of suitable surfactants are Tween and Triton. The fermentation is
therefore preferably conducted in the presence of such surfactants.
Furthermore, yields are noted to be improved when the fermentation of
Hansenula ciferrii is carried out in the presence of selected precursors
e.g. palmitic acid, serine and mixtures thereof. The fermentation is
therefore preferably conducted in the presence of such precursors.
Preferably the non-fermentable carbon source is glycerol. Use of a
non-fermentable carbon source improves the biomass titres (g cells/liter
fermentation broth) and hence the productivity of the reaction (eg
TAPS/liter). TAPS is conveniently extracted from the fermentation products
by solvent extraction.
The fermentation process produces a mixture of products, namely
phytosphingosines with some sphingosines, of mixed chain lengths. The main
product is TAPS, with some triacetylphytosphingosine and also some
triacetylsphingosine. The products are a mixture of C.sub.16-20 of odd and
even chain length, mainly straight chain but possibly with some branched
chain products. The main product is C.sub.18 straight chain TAPS.
TAPS can be readily converted to phytosphingosine by a suitable
deacetylation reaction, as is well known to those skilled in the field,
e.g. by base catalysed hydrolysis for example using potassium hydroxide.
The phytosphingosine obtained via fermentation of Hansenula ciferrii is
then used for the preparation of phytosphingosine-containing ceramide one.
The use of phytosphingosine obtained by fermentation for this preparation
is particularly advantageous to the use of other sources of
phytosphingosine (e.g. chemically synthesised) because the
phytosphingosine obtained by fermentation is the D-D-erythro isomer, the
same as occurs in human skin. Other methods of preparation of
phytosphingosine produce a mixture of stereoisomers which must be
separated prior to use. Accordingly use of phytosphingosine obtained by
fermentation for the preparation of ceramide one provides a very simple,
cost effective method.
Alpha hydroxy fatty acids are also produced in the fermentation reaction.
The acids are produced in a range of chain lengths from about C.sub.16-24.
The amount of acids produced can be controlled by varying the carbon
source: more is produced from glucose than glycerol. The acids can be
separated and used in the production of component (2) for production of
ceramide one.
The fatty acid/hydroxy fatty acid component of ceramide one has the general
structure (2) shown above. Component (2) can be produced by esterifying
.omega.-hydroxy acid with fatty acid or fatty acyl chloride.
Synthesis of .omega.-hydroxy fatty acid of suitable chain length can be
effected, for example, by using Kolbe synthesis to link together the half
esters of two dioic acids, to produce the diester of a longer chain dioic
acid. After hydrolysis to the half ester the molecule can then be reduced
to produce an omega hydroxy long chain fatty acid. The two dioic acids
used can be the same or different. For example, two C.sub.16 dioic acids
can be linked to form a C.sub.30 acid, two C.sub.12 dioic acids can be
linked to form a C.sub.22 acid, etc. The reaction scheme is shown in FIG.
4.
Alternatively, a dioic acid half ester can be linked to an .omega.-hydroxy
monocarboxylic acid by Kolbe synthesis to produce a longer chain
.omega.-hydroxy acid. For example C.sub.16 dioic acid half ester and
C.sub.16 omega hydroxy monocarboxylic acid produce C.sub.30 omega hydroxy
acid.
Alternatively two .omega.-hydroxy fatty acids may be coupled to give a long
chain diol, followed by partial oxidation to give a long chain
.omega.-hydroxy fatty acid.
The long chain fatty acid/.omega.-hydroxy fatty acid component (2) of
ceramide 1 can be made in a two stage process, for example by first
linking two C.sub.16 dioic (dicarboxylic) acid half esters followed by
reduction to produce a C.sub.30 omega hydroxy acid and then linking
linoleic acid (which is commercially available, e.g. derived from plant
oil such as sunflower oils) by an esterification reaction to produce the
long chain acid. The linoleic acid is preferably activated, for example,
in the form of an acyl chloride.
It will thus be seen that this approach is very versatile and can enable
production of a wide range of long chain fatty acid/.omega.-hydroxy fatty
acid components of general structure (2).
Kolbe synthesis reactions are well known to those skilled in the art, and
details will not be given here.
Dioic acids are conveniently obtained by biochemical oxidation of
monocarboxylic fatty acids, e.g. using Candida cloacae, for example as
disclosed in EP 0 341 796.
The phytosphingosine base and fatty acid component/hydroxy fatty acid (2)
can be readily linked by chemical or enzymic routes, e.g. using
conventional N acylation reactions.
For example, a simple amidation reaction can be carried out, possibly acid
or base catalysed or possibly non-catalysed after carboxyl group
activation. For instance, the fatty acid component can be converted to the
methyl ester and reacted, under vacuum with heating, with the
phytosphingosine base and sodium methoxide catalyst. This reaction is
found to be simple, straightforward and effective, giving a good yield of
product, and furthermore does not require the presence of a solvent.
Component (2) may alternatively be reacted in the form of the acid chloride
or using an activating reagent such as 2-chloromethyl pyridium iodide.
Enzymic routes are also possible.
The order of reaction steps is not critical. For example a component (2)
may be synthesised from shorter components, as described above, and then
coupled to the phytosphingosine base. Alternatively, a .omega.-hydroxy
fatty acid component may be linked to the phytosphingosine base prior to
esterification of the .omega.-hydroxyl group.
It will be apparent that the invention provides the potential for
production of a wide range of phytosphingosine-containing ceramide one
structures, both identical to those found in nature and of novel
structure.
In a further aspect, the present invention provides a
phytosphingosine-containing ceramide one produced by the method of the
invention, and derivatives thereof.
The phytosphingosine-containing ceramide one structures find particular
application in the treatment of skin, hair and nails.
In a further aspect, the invention thus provides a cosmetic composition
suitable for topical application to skin, hair or nails comprising:
(i) an effective amount of from 0.00001 to 50% by weight of a
phytosphingosine-containing ceramide one having the general structure (1):
##STR6##
where R represents a linear or branched, saturated or unsaturated,
hydroxylated or non-hydroxylated aliphatic hydrocarbon having from 8 to 28
carbon atoms;
R.sub.1 represents H, a phosphate residue, a sulphate residue or a sugar
residue
Z is --OH or an epoxy oxygen
a is an integer of from 7 to 50
b is an integer of from 10 to 100
m is 0 or 1
x is an integer of from 12 to 20
y is an integer of from 20 to 40
z is 0 or an integer of from 1 to 4
wherein the phytoshingosine-containing ceramide one is synthesised
according to the invention; and
(ii) a cosmetically acceptable vehicle for the phytosphingosine-containing
ceramide one.
With reference to structure (1) the group R preferably represents an
aliphatic hydrocarbon group having from 12 to 22 carbon atoms.
With reference to structure (1), the value of "a" is preferably an integer
of from 24 to 30 and the value of "b" is preferably an integer of from 44
to 60.
Structure (4) preferably represents a straight chain saturated C.sub.16-18,
fatty acid residue or a straight chain all cis n-6,9 di-unsaturated
C.sub.16-18 fatty acid residue.
Specific examples of these phytosphingosine-containing ceramide one
structures are those having the structures (5) to (10):
##STR7##
The amount of the phytosphingosine-containing ceramide one present in the
composition according to the invention is from 0.00001 to 50%, preferably
from 0.001 to 20% and most preferably from 0.1 to 10% by weight.
THE COSMETICALLY ACCEPTABLE VEHICLE
The composition according to the invention also comprises a cosmetically
acceptable vehicle to act as a dilutant, dispersant or carrier for the
phytosphingosine-containing ceramide one, so as to facilitate its
distribution when the composition is applied to the skin and/or hair.
Vehicles other than water can include liquid or solid emollients, solvents,
humectants, thickeners and powders. Examples of each of these types of
vehicle, which can be used singly or as mixtures of one or more vehicles,
are as follows:
Emollients, such as stearyl alcohol, glyceryl monoricinoleate, glyceryl
monostearate, mink oil, cetyl alcohol, isopropyl isostearate, stearic
acid, isobutyl palmitate, isocetyl stearate, oleyl alcohol, isopropyl
laurate, hexyl laurate, decyl oleate, octadecan-2-ol, isocetyl alcohol,
eicosanyl alcohol, behenyl alcohol, cetyl palmitate, silicone oils such as
dimethylpolysiloxane, di-n-butyl sebacate, isopropyl myristate, isopropyl
palmitate, isopropyl stearate, butyl stearate, polyethylene glycol,
triethylene glycol, lanolin, cocoa butter, corn oil, cotton seed oil,
tallow, lard, olive oil, passion flower oil, palm kernel oil, rapeseed
oil, safflower seed oil, evening primrose oil, soybean oil, sunflower seed
oil, avocado oil, olive oil, sesame seed oil, coconut oil, arachis oil,
castor oil, acetylated lanolin alcohols, petroleum jelly, mineral oil,
butyl myristate, isostearic acid, palmitatic acid, isopropyl linoleate,
lauryl lactate, myristyl lactate, decyl oleate, myristyl myristate;
Propellants, such as air, propane, butane, isobutane, dimethyl ether,
carbon dioxide, nitrous oxide;
Solvents, such as ethyl alcohol, methylene chloride, isopropanol, acetone,
ethylene glycol monoethyl ether, diethylene glycol monobutyl ether,
diethylene glycol monoethyl ether, dimethyl sulphoxide, dimethyl
formamide, tetrahydrofuran;
Powders, such as chalk, talc, fullers earth, kaolin, starch, gums,
colloidal silica sodium polyacrylate, tetra alkyl and/or trialkyl aryl
ammonium smectites, chemically modified magnesium aluminium silicate,
organically modified montmorillonite clay, hydrated aluminium silicate,
fumed silica, carboxyvinyl polymer, sodium carboxymethyl cellulose,
ethylene glycol monostearate.
The cosmetically acceptable vehicle will usually form from 10 to 99.9%,
preferably from 50 to 99% by weight of the emulsion, and can, in the
absence of other cosmetic adjuncts, form the balance of the composition.
OPTIONAL SKIN BENEFIT MATERIALS AND COSMETIC ADJUNCTS
A particularly convenient form of the composition according to the
invention is an emulsion, in which case an oil or oily material will
normally be present, together with an emulsifier to provide either a
water-in-oil emulsion or an oil-in-water emulsion, depending largely on
the average hydrophillic-lyophilic balance (HLB) of the emulsifier
employed.
OIL OR OILY MATERIAL
The composition according to the invention can optionally comprise one or
more oils or other materials having the properties of an oil.
Examples of suitable oils include mineral oil and vegetable oils, and oil
materials, such as those already proposed herein as emollients. Other oils
or oily materials include silicone oils, both volatile and non-volatile,
such as polydimethyl siloxanes.
The oil or oily material, when present for the purposes for forming an
emulsion, will normally form up to 90%, preferably from 10 to 80% by
volume of the composition.
EMULSIFIER
The composition according to the invention can also optionally comprise one
or more emulsifiers the choice of which will normally determine whether a
water-in-oil or and oil-in-water emulsion is formed.
When a water-in-oil emulsion is required, the chosen emulsifier or
emulsifiers should normally have an average HLB value of from 1 to 6. When
an oil-in-water emulsion is required, a chosen emulsifier or emulsifiers
should have an average HLB value of >6.
Examples of suitable emulsifiers are set below in Table 1 in which the
chemical name of the emulsifiers is given together with an example of a
trade name as commercially available, and the average HLB value.
TABLE 1
______________________________________
Chemical Name of Emulsifier
Trade Name HLB Value
______________________________________
Sorbitan trioleate Arlacel 85 1.8
Sorbitan tristearate
Span 65 2.1
Glycerol monooleate
Aldo MD 2.7
Glycerol monostearate
Atmul 84S 2.8
Glycerol monolaurate
Aldo MC 3.3
Sorbitan sesquioleate
Arlacel 83 3.7
Sorbitan monooleate
Arlacel 80 4.3
Sorbitan monostearate
Arlacel 60 4.7
Poloxyethylene (2) stearyl ether
Brij 72 4.9
Poloxyethylene sorbitol beeswax
G-1702 5
derivative
PEG 200 dilaurate Emerest 2622
6.3
Sorbitan monopalmitate
Arlacel 40 6.7
Polyoxyethylene (3.5) nonyl phenol
Emulgen 903 7.8
PEG 200 monostearate
Tegester PEG
8.5
200 MS
Sorbitan monolaurate
Arlacel 200 8.6
PEG 400 dioleate Tegester PEG
8.8
400-DO
Polyoxyethylene (5) monostearate
Ethofat 60-16
9.0
Polyoxyethylene (4) sorbitan mono-
Tween 61 9.6
stearate
Polyoxyethylene (4) lauryl ether
Brij 30 9.7
Polyoxyethylene (5) sorbitan mono-
Tween 81 10.0
oleate
PEG 300 monooleate Neutronyx 834
10.4
Polyoxyethylene (20) sorbitan tri-
Tween 65 10.5
stearate
Polyoxyethylene (20) sorbitan tri-
Tween 85 11.0
oleate
Polyoxyethylene (8) monostearate
Myrj 45 11.1
PEG 400 monooleate Emerest 2646
11.7
PEG 400 monostearate
Tegester PEG
11.9
400
Polyoxyethylene 10 monooleate
Ethofat 0/20
12.2
Polyoxyethylene (10) stearyl ether
Brij 76 12.4
Polyoxyethylene (10) cetyl ether
Brij 56 12.9
Polyoxyethylene (9.3) octyl phenol
Triton X-100
13.0
Polyoxyethylene (4) sorbitan mono-
Tween 21 13.3
laurate
PEG 600 monooleate Emerest 2660
13.7
PEG 1000 dilaurate Kessco 13.9
Polyoxyethylene sorbitol lanolin
G-1441 14.0
derivative
Polyoxyethylene (12) lauryl ether
Ethosperse 14.4
LA-12
PEG 1500 dioleate Pegosperse 1500
14.6
Polyoxyethylene (14) laurate
Arosurf HFL-
14.8
714
Polyoxyethylene (20) sorbitan
Tween 14.9
monostearate
Polyoxyethylene 20 sorbitan mono-
Tween 80 15.0
oleate
Polyoxyethylene (20) stearyl ether
Brij 78 15.3
Polyoxyethylene (20) sorbitan
Tween 40 15.6
monopalmitate
Polyoxyethylene (20) cetyl ether
Brij 58 15.7
Polyoxyethylene (25) oxypropylene
G-2162 16.0
monostearate
Polyoxyethylene (20) sorbitol
Tween 20 16.7
monolaurate
Polyoxyethylene (23) lauryl ether
Brij 35 16.9
Polyoxyethylene (50) monostearate
Myrj 53 17.9
PEG 4000 monostearate
Pegosperse 4000
18.7
MS
______________________________________
The foregoing list of emulsifiers is not intended to be limiting and merely
exemplifies selected emulsifiers which are suitable for use in accordance
with the invention.
It is to be understood that two or more emulsifiers can be employed if
desired.
The amount of emulsifier or mixtures thereof, to be incorporated in the
composition of the invention, when appropriate is from 1 to 50%,
preferably from 2 to 20% and most preferably from 2 to 10% by weight of
the composition.
WATER
The composition of the invention can also comprise water, usually up to
98%, preferably from 5 to 80% by volume.
SILICONE SURFACTANT
The composition of the invention can also optionally comprise a high
molecular weight silicone surfactant which can also act as an emulsifier,
in place of or in addition to the optional emulsifier(s) already
mentioned.
The silicone surfactant is a high molecular weight polymer of dimethyl
polysiloxane with polyoxyethylene and/or polyoxypropylene side chains
having a molecular weight of from 10,000 to 50,000 and having the
structure:
##STR8##
where the groups R' and R" are each chosen from --H, C.sub.1-18 alkyl and
##STR9##
e has a value of from 9 to 115,
f has a value of from 0 to 50,
c has a value of from 133 to 673,
d has a value of from 25 to 0.25.
Preferably, the dimethyl polysiloxane polymer is one in which:
e has a value of from 10 to 114
f has a value of from 0 to 49
c has a value of from 388 to 402
d has a value of from 15 to 0.75
one of groups R' and R" being lauryl, and the other having a molecular
weight of from 1000 to 5000.
A particularly preferred dimethyl polysiloxane polymer is one in which:
e has the value 14
f has the value 13
c has the value 249
d has the value 1.25
The dimethyl polysiloxane polymer is conveniently provided as a dispersion
in a volatile siloxane, the dispersion comprising, for example, from 1 to
20% by volume of the polymer and from 80 to 99% by volume of the volatile
siloxane. Ideally, the dispersion consists of a 10% by volume of the
polymer dispersed in the volatile siloxane.
Examples of the volatile siloxanes in which the polysiloxane polymer can be
dispersed include polydimethyl siloxane (pentamer and/or hexamer).
A particularly preferred silicone surfactant is cyclomethicone and
dimethicone copolyol, such as DC 3225C Formulation Aid available from DOW
CORNING. Another is laurylmethicone copolyol, such as DC Q2-5200, also
available from Dow Corning.
The amount of silicone surfactant, when present in the composition will
normally be up to 25%, preferably from 0.5 to 15% by weight of the
emulsion.
OTHER COSMETIC ADJUNCTS
Examples of conventional adjuncts which can optionally be employed include
preservatives, such as para-hydroxy benzoate esters; antioxidants, such
butyl hydroxy toluene; humectants, such as glycerol, sorbitol,
2-pyrrolidone-5-carboxylate, dibutylphthalate, gelatin, polyethylene,
glycol, preferably PEG 200-600; buffers, such as lactic acid together with
a base such as triethanolamine or sodium hydroxide; surfactants, such as
glycerol ethers and other ceramides of synthetic, animal or plant origin;
phospholipids; waxes, such as beeswax, ozokerite wax, paraffin wax, plant
extracts, such as Aloe vera, cornflower, witch hazel, elderflower,
cucumber; thickeners; activity enhancers; colourants; perfumes; and
sunscreen materials such as ultrafine titanium dioxide and organic
sunscreens such as p-aminobenzoic acid and esters thereof, ethylhexyl
p-methoxycinnamate, 2-ethoxyethyl p-methoxycinnamate and butyl
methoxydibenzoylmethane, and mixtures thereof.
In a further preferred composition, the phytosphingosine-containing
ceramide one is combined with conventional ceramides, pseudoceramides,
polyol fatty acid polyesters, sterols particularly cholesterol,
galactosyldiacylglycerols, glycosphingolipids, fatty acids and esters
thereof, triglycerides, cerebroside, phospholipid and other ingredients
well known to those skilled in the art to produce a liposomal dispersion
or bilayer structure.
A preferred composition may also contain, in combination with the
phytosphingosine containing ceramide one and optional additional
ingredients disclosed above, an organic acid component chosen from hydroxy
carboxylic acids, keto carboxylic acids, esters thereof and mixtures
thereof.
In yet another preferred composition, the phytosphingosine-containing
ceramide one is dissolved in squalene or squalane, optionally together
with conventional ceramides, and formulated with volatile and non-volatile
silicones to produce an anhydrous or nearly anhydrous single phase system.
Cosmetic adjuncts can form the balance of the composition.
USE OF THE COMPOSITION
The composition according to the invention is intended primarily as a
product for topical application to human skin, especially as an agent for
reducing the permeability to water of the skin, particularly when the skin
is dry or damaged, in order to reduce moisture loss and generally to
enhance the quality and flexibility of skin. The composition can also be
applied to hair and nails.
The composition may therefore be used as a product for topical application
to human skin to treat dry, detergent-damaged or ageing skin.
In use, a small quantity of the composition, for example from 1 to 5 ml, is
applied to exposed areas of the skin, from a suitable container or
applicator and, if necessary, it is then spread over and/or rubbed into
the skin using the hand or fingers or a suitable device.
PRODUCT FORM AND PACKAGING
The topical skin, hair or nail treatment composition of the invention can
be formulated as a lotion having a viscosity of from 4,000 to 10,000 mPas,
a fluid cream having a viscosity of from 10,000 to 20,000 mPas or a cream
having a viscosity of from 20,000 to 100,000 mPas, or above. The
composition can be packaged in a suitable container to suit its viscosity
and intended use by the consumer.
For example, a lotion or fluid cream can be packaged in a bottle or a
roll-ball applicator or a propellant-driven aerosol device or a container
fitted with a pump suitable for finger operation. When the composition is
a cream, it can simply be stored in a non-deformable bottle or squeeze
container, such as a tube or a lidded jar.
The invention accordingly also provides a closed container containing a
cosmetically acceptable composition as herein defined.
EXAMPLES
The invention will be further described by way of illustration, in the
following examples and by reference to the accompanying drawings in which:
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a flow chart illustrating the isolation and purification of TAPS;
FIG. 2 and 3 are graphs of TAPS production versus increasing cell mass in a
fermenter showing that TAPS formation is growth-associated, i.e. the
amount of TAPS formed is directly proportional to the amount of cells
grown;
FIG. 4 illustrates the half ester route for production of component 2; and
FIG. 5 illustrates schematically production of ceramide 1 by the method of
the invention.
EXAMPLE 1
Synthesis of C.sub.22 hydroxy fatty acid from dodecanedioic acid
A solution of dodecanedioic acid (100 g) in methanol (400 ml) was reacted
at 70.degree. C. with a solution of borontrifluoride in methanol (14%, 70
ml). After 1 hour excess methanol was removed and the dioic diester
product recrystallised from petroleum ether (60.degree.-80.degree.) (200
ml). The product was more than 99% pure in a yield of 95%.
Diester (100 g) was hydrolysed with half mole equivalent of KOH (400 ml,
90:5 methanol:water) at 70.degree. C. for 1 hour. The reaction mix was
subsequently neutralised with 1N HCl and then the aqueous phase removed by
filtration. The reaction product consisting of monoester (1/2 acid ester),
diester and diacid was dissolved in 60.degree.-80.degree. petroleum ether.
Diacid was found to be barely soluble and was removed by filtration. The
half acid ester was recrystallised twice as it was only 85% pure from one
recrystallisation. The yield of half acid ester recovered pure was 52%.
The reaction product was analysed by GC and IR spectroscopy. Remaining
diacid, diester and impure half acid ester was recycled to give an overall
yield after one recycle of 67%.
With pure half acid ester available it was possible to effect a Kolbe
electrolysis to synthesise the C.sub.22 dimethyl ester.
A solution of dodecanedioic acid half ester (10 g in 80 ml methanol) was
partially neutralised with 0.1 equivalent of KOH in water (8 ml). The
resulting solution was electrolysed at 120 volts and an initial current of
0.9 amps between 2 platinum electrodes 4cm.times.0.5cm.times.0.1 mm. The
electrodes were set 2-3 mm apart and were constructed with a platinum/wire
junction sealed in glass to isolate it from the reaction medium. On
cooling to 0.degree. C. product was found to precipitate. Reaction was
carried out for 4-6 hours. The collected product was recrystallised from
petroleum ether 60.degree.-80.degree.. The final yield of C.sub.22 diester
was 5 g (yield 60%, purity 80%) in this case.
With the long chain ester available the next step is selectively to reduce
one end of the molecule. This was achieved by partial hydrolysis as
before, followed by reduction of the ester moiety using lithium
borohydride.
C.sub.22 diester (1 g) was initially reacted with a half mole equivalent of
KOH in methanol/water 90:10 (50 ml) at 70.degree. C. The half acid ester
was purified as before. Yield of isolated half acid ester was 300 mg (80%
pure, total yield 31%).
The half ester obtained was dissolved in dry diethyl ether (5 ml) and
reacted with 1 mole equivalent of lithium borohydride in dry diethyl ether
(5 ml, 10% w/v). After 24 hours, reaction was stopped by addition of 1N
HCl (2 ml). Diethyl ether was removed and the product washed with water
and dried under vacuum. The crude mix was dissolved in ethanol (5 ml,
60.degree. C.) and water added until turbidity was present. The C.sub.22
product crystallised out and was filtered off. GCMS of this product showed
that it was predominantly omega-hydroxy C.sub.22 acid. Purity by GC was
74%-84%. C.sup.13 and H.sup.1 NMR also confirmed the authenticity of the
product.
EXAMPLE 2
Synthesis of Phytosphingosine-containing ceramide one
Preparation of Phytosphingosine
The yeast Hansenula (Pichia) ciferrii (mating type F-60-10) obtained from
the Northern Regional Research Labs, Peoria, Ill., USA was grown up under
suitable conditions. A 1% v/v inoculum was added to the fermenter (working
volume 3.51) containing a growth medium comprising:
Glycerol, 30 gl.sup.-1 ; KH.sub.2 PO.sub.4, 6.4 gl.sup.-1 ;
(NH.sub.4).sub.2 HPO.sub.4, 4 gl.sup.-1 ; and Na.sub.2 SO.sub.4, 1.5
gl.sup.-1 ; together with the trace nutrients pantothenate, 6 mgl.sup.-1 ;
thiamine, 8 mgl.sup.-1 ; nicotinic acid 30 mgl.sup.-1 ; pyridoxine, 20
mgl.sup.-1 and biotin, 100 .mu.gl.sup.-1. In addition some yeast extract
was required, particularly to maintain cell growth during extended
fermenter runs. Typically 3 gl.sup.-1 yeast extract was added.
Fermentation was carried out at 30.degree. C. with 0.5 v/v/min air
supplied. The fermentation was characterised by the production of copious
foam which was combatted by the addition of antifoam and/or by the use of
a lower fermenter working volume. The course of the fermentation was
continuously monitored by gas analysis, and also by glc analysis of timed
samples for remaining glycerol and tetraacetylphytosphingosine (TAPS) and
other metabolites produced. Additional glycerol was added at intervals, as
indicated by the gas analyses, so as to maintain growth and produce as
high biomass concentration as possible (greater than or equal to 50-55 gdw
1.sup.-1).
Once these high biomass concentrations were reached the broth was
centrifuged at 3500 rpm at 10.degree. C. or 20.degree. C., and the cell
pellet freeze-dried so as to facilitate solvent extraction.
ISOLATION AND PURIFICATION OF TAPS
The freeze-dried cells were ground with MeOH/EtOAc (l/l, v/v) at 60.degree.
C. and then filtered, and this extraction and filtration repeated. (85% of
the TAPS was recovered in the first extraction.) The combined filtrates
were evaporated under reduced pressure to produce a crude solid extract
(30 g from 174 gd cells, equivalent to 690 gw cells). This solid extract
was redissolved in hot EtOAc (0.5 l) and partitioned with 0.5 l of water,
so as to remove water-soluble impurities; these include a sugar, probably
xylitol, in significant amounts. The EtOAc phase was evaporated to dryness
to produce 16.9 g of lipid extract containing alpha-HPA, cholesterol and
ergosterol as metabolic side-products, plus large amounts of silicone
antifoam carried over from the fermentation.
Optionally the fermentation supernatant (2.69 l) could also be extracted
with EtOAc (2.5 l) to produce 1.49 g of lipid extract with a similar TAPS
composition to that of the cell extract.
These extracts could be combined and dissolved in 75 ml of warm light
petroleum (60.degree.-80.degree. C.) and chromatographed on a column of
100 g of 70-230 mesh silica gel. Elution with more petroleum (400 ml)
eluted the antifoam. Elution with light petroleum -30% diethyl ether (800
ml) removed the alpha-HPA and sterols, and then finally light
petroleum--60% diethyl ether (1.2 l) eluted with the TAPS in 94% yield and
over 95% purity. Phytosphingosines with varying side chains, some
triacetylsphingosine and also some triacetylphytosphingosine were also
present.
The isolation and purification of TAPS is illustrated in FIG. 1. TAPS
production is illustrated graphically in FIGS. 2 and 3 including results
for glycerol and glucose carbon sources. FIG. 3 gives results using
glycerol only, and shows that the amount of TAPS formed is directly
proportional to the amount of cells grown.
The process described is much more efficient than the prior art process.
Results are shown in Tables 2 and 3.
TABLE 2
______________________________________
Comparison of Prior Art (Best-Case) & Present TAPS
Fermentations
PRESENT INVENTION
PRIOR ART
BATCH FED-BATCH
______________________________________
Yield of TAPS from
5 20 22
glucose/glycerol
(mg/g)
Yield of TAPS on bio-
15 40 44
mass (mg/gdw)
Max broth concentra-
307 600 2700
tion (mgl.sup.-1)
Volumetric productiv-
3.2* 13.3 22.5
ity (mg TAPS l.sup.-1
h.sup.-1)
______________________________________
*Excludes 65 h postfermentation incubation required to facilitate
extraction of TAPS, otherwise 2.25 mg l.sup.-1 h.sup.-1.
TABLE 3
__________________________________________________________________________
TAPS Fermentation Productivities
TEMPERATURE
BATCH vs TAPS TITRE
BIOMASS CONC
SPECIFIC YIELD OF
CARBON SOURCE
(.degree.C.)
FED-BATCH
(mg l.sup.- 1)
(gdw l.sup.-1)
TAPS (mg/gdw
__________________________________________________________________________
cells)
Glucose 25 Batch 30 6-8 6.5
Glucose (pure strain of
25 Batch 100 8.3 12
H ciferrii used)
Glycerol 25 Batch 200-250 12 17-21
Glycerol 30 Batch 1,000 22 59
Glycerol 30 Fed-Batch
2,700 50-55 45-55
Glycerol plus methanol
30 Batch 720 12 60
Glycerol plus methanol
30 Fed-Batch
2083 34 61
Glycerol, methanol
30 Batch 1207 14 86
0.2% w/v palmitic acid
0.2% w/v serine
__________________________________________________________________________
DEACETLYATION
0.9g TAPS was refluxed with 1 g KOH in ethanol/water (9/L v/v) (20 ml) for
5h. The solvent was removed under vacuum and the phytosphingosine produced
extracted into diethyl ether Glc and nmr analysis showed that the
phytosphingosine was obtained in 95% purity at a yield of 81%.
COUPLING PHYTOSPHINGOSINE TO COMPONENT (2)
The phytosphingosine as produced above was coupled to a fatty
acid/.omega.-hydroxy fatty acid component (2). The component (2) was
synthesised via ester formation. A broad range of types of component (2)
are possible, long chain hydroxy acids being obtained as in Example 1. For
ease of analysis of the final phytosphingosine-containing ceramide 1
product, in this example we synthesised a ceramide where component (2) was
produced from decanoyl chloride and 12-hydroxy dodecanoic acid to give the
C.sub.10 C.sub.12 acid ester.
12-hydroxydodecanoic acid (2.5 g) was dissolved in petrol
60.degree.-80.degree. (25 ml) and to this solution was added decanoyl
chloride (2.2 g) and pyridine (1 ml). After 3 hours the reaction was
stopped. The mixture was run through basic alumina II (45 g) which removed
any shorter chain reactants remaining. The alumina was washed with diethyl
ether. 1.5 g of product (99% by GC) was recovered (yield 35%).
Confirmation of structure was by GCMS which was entirely consistent with
the expected ion fragmentation pattern for the C.sub.10 C.sub.12 ester.
The C.sub.10 C.sub.12 acid ester (5 mg) was dissolved in dichloromethane
(0.5 ml) together with phytosphingosine (4 mg) and 2-chloromethyl pyridium
iodide (4 mg). To this mixture was added 5 .mu.l triethylamine- The
reaction was left at RT for 1 hour then washed 3 times with water (5 ml).
The dichloromethane layer was dried over 4A molecular sieve and evaporated
to dryness. The residue 9.7 mg of tan white powder was analyzed by GCMS.
Yield 115%, purity 85% by GC. The major product was the C.sub.10 C.sub.12
ceramide 1 as evidenced by GCMS ion fragmentation patterns.
EXAMPLE 3
This example illustrates a high internal phase water-in-oil emulsion in
accordance with the invention.
A high internal phase water-in-oil emulsion having the following
formulation was prepared:
______________________________________
% w/w
______________________________________
Fully hydrogenated coconut oil
3.9
Phytosphingosine-containing ceramide one having the
0.1
structure (5)
Brij 92* 5
Bentone 38 0.5
Preservative 0.3
MgSO.sub.4 7H.sub.2 O 0.3
Butylated hydroxy toluene 0.01
Perfume qs
Water to 100
______________________________________
*Brij 92 is polyoxyethylene (2) oleyl ether
EXAMPLE 4
This example also illustrates a high internal phase water-in-oil emulsion
in accordance with the invention in which the formulation of Example 3 was
prepared but with the following changes:
i. liquid paraffin replaced the fully hydrogenated coconut oil, and
ii. the phytosphingosine-containing ceramide one had the structure (6).
EXAMPLE 5
This example illustrates an oil-in-water cream emulsion having the
following formulation:
______________________________________
% w/w
______________________________________
Mineral oil 4
Phytosphingosine-containing ceramide one having the
0.1
structure (7)
Brij 56* 4
Alfol 16RD* 4
Triethanolamine 0.75
Butane-1,3-diol 3
Xanthan gum 0.3
Preservative 0.4
Perfume qs
Butylated hydroxy toluene 0.01
Water to 100
______________________________________
*Brij 56 is cetyl alcohol POE (10)
Alfol 16RD is cetyl alcohol
EXAMPLE 6
This example illustrates an alcoholic lotion. The lotion had the following
formulation:
______________________________________
% w/w
______________________________________
Phytosphingosine-containing ceramide one having the
0.2
structure (8)
Ethanol 40
Perfume qs
Butylated hydroxy toluene 0.01
Water to 100
______________________________________
EXAMPLE 7
This example illustrates an alcoholic lotion. The lotion had the following
formulation:
______________________________________
% w/w
______________________________________
Phytosphingosine-containing ceramide one having the
0.2
structure (9)
Dimethylsulphoxide 10
Ethanol 40
Antioxidant 0.1
Perfume qs
Water to 100
______________________________________
EXAMPLE 8
The following composition according to the invention represent a lotion
which can be used in the treatment of dry or ageing skin:
______________________________________
% w/w
______________________________________
Phytosphingosine-containing ceramide one having the
1.0
structure (10)
Sphingosine-containing ceramide
0.5
Perfume 0.1
Hydroxyethyl cellulose 0.4
Absolute ethanol 25
p-methyl benzoate 0.2
Sterilised demineralised water
to 100
______________________________________
EXAMPLE 9
The following compositions according to the invention represent lotions
which can be used in the treatment of dry or ageing skin:
______________________________________
% w/w
______________________________________
The phytosphingosine-containing ceramide one having
0.08
the structure (5)
Pseudo ceramide 0.15
Ethanol 10
Perfume 0.5
Distilled water to 100
______________________________________
EXAMPLE 10
This example illustrates a high internal phase water-in-oil emulsion in
accordance with the invention.
A high internal phase water-in-oil emulsion having the following
formulation was prepared:
______________________________________
% w/w
______________________________________
Fully hydrogenated coconut oil
3.9
Phytosphingosine-containing ceramide one having the
0.1
structure (6)
Brij 92* 5
Bentone 38 0.5
Preservative 0.3
MgSO.sub.4 7H.sub.2 O 0.3
Butylated hydroxy toluene 0.01
Perfume qs
Water to 100
______________________________________
*Brij 92 is polyoxyethylene (2) oleyl ether
EXAMPLE 11
This example also illustrates a high internal phase water-in-oil emulsion
in accordance with the invention in which the formulation of Example 3 was
prepared but with the following changes:
i. liquid paraffin replaced the fully hydrogenated coconut oil, and
ii. the phytosphingosine-containing ceramide one had the structure (6).
EXAMPLE 12
This example illustrates an oil-in-water cream emulsion having the
following formulation:
______________________________________
% w/w
______________________________________
Mineral oil 4
Phytosphingosine-containing ceramide one having the
0.05
structure (7)
Phytosphingosine-containing ceramide one having the
0.05
structure (8)
Brij 56* 4
Alfol 16RD* 4
Triethanolamine 0.75
Butane-1,3-diol 3
Xanthan gum 0.3
Preservative 0.4
Perfume qs
Butylated hydroxy toluene 0.01
Water to 100
______________________________________
*Brij 56 is cetyl alcohol POE (10)
Alfol 16RD is cetyl alcohol
EXAMPLE 13
This example illustrates an alcoholic lotion containing a
phytosphingosine-containing ceramide one of the invention.
The lotion had the following formulation:
______________________________________
% w/w
______________________________________
Phytosphingosine-containing ceramide one having the
0.2
structure (9)
Ethanol 40
Perfume qs
Butylated hydroxy toluene 0.01
Water to 100
______________________________________
EXAMPLE 14
This example illustrates an alcoholic lotion which is suitable for
application to nails.
The lotion had the following formulation:
______________________________________
% w/w
______________________________________
Phytosphingosine-containing ceramide one having the
0.2
structure (10)
Dimethylsulphoxide 10
Ethanol 40
Antioxidant 0.1
Perfume qs
Water to 100
______________________________________
EXAMPLE 15
The following composition according to the invention represent a lotion
which can be used in the treatment of dry, unmanageable hair.
______________________________________
% w/w
______________________________________
Phytosphingosine-containing ceramide one having the
1.0
structure (9)
Pseudoceramide 0.5
Perfume 0.1
Hydroxyethyl cellulose 0.4
Absolute ethanol 25
p-methyl benzoate 0.2
Sterilised demineralised water
to 100
______________________________________
EXAMPLE 16
The following compositions according to the invention represent lotions
which can be used in the treatment of dry skin, hair or nails:
______________________________________
% w/w
______________________________________
The phytosphingosine-containing ceramide one having
0.08
the structure (10)
Ethanol 10
Perfume 0.5
Distilled water to 100
______________________________________
EXAMPLE 17
In vitro efficacy studies--water vapour transmission rate (WVTR)
C.sub.30 linoleic phytosphingosine-containing ceramide 1 (structure 6) was
prepared according to the invention. The reduction in water permeability
through "Acetate Plus" membranes (from Micron Separation Inc, having 25 mm
diameter and 5 .mu.m pore size) following topical application of a
composition comprising C.sub.30 linoleic phytosphingosinecontaining
ceramide was determined by in vitro measurement of the water vapour
transmission rate (WVTR) using a similar system to that described by Blank
et al (J Invest Dermatol 18 (1952) 433-440.
The C.sub.30 linoleic phytosphingosine-containing ceramide was formulated
in an oil in water emulsion containing cholesterol, stearic acid and
sodium stearate (1:2:0.7:0.3 wt %) together with glycerol (1%) (Example
17) and compared with an identical emulsion except C.sub.30 linoleoyl
phytosphingosine-containing ceramide 1 was replaced by cholesterol (i.e.
cholesterol:stearic acid and sodium stearate 3:0.7:0.3 wt % plus glycerol
1%) (comparative Example A).
Approximately 15 mgs of each aqueous formulation was applied to the
membrane and allowed to dry. The membranes are weighed, and amounts of
applied formulations adjusted accordingly, to ensure comparable amounts of
material are applied to each membrane. Experiments are performed in
triplicate.
Membranes with and without product applied are then applied to the WVTR
cells with water in the wells of the cells, weighed and placed in a
desiccator for 20 hours. The rate and amount of water loss is then
determined from the change in weight of the diffusion cells. Barrier
efficiency is demonstrated by the difference in weight loss of the treated
and nontreated membranes represented as a percentage improvement in
barrier efficiency.
Results are shown in Table 4.
TABLE 4
______________________________________
Example % improvement in barrier function
______________________________________
17 9.74 .+-. 0.31*
A 6.50 .+-. 0.24
______________________________________
*P < 0.05
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